arm64/mm/hotplug: Register boot memory hot remove notifier earlier

This moves memory notifier registration earlier in the boot process from
device_initcall() to early_initcall() which will help in guarding against
potential early boot memory offline requests. Even though there should not
be any actual offlinig requests till memory block devices are initialized
with memory_dev_init() but then generic init sequence might just change in
future. Hence an early registration for the memory event notifier would be
helpful. While here, just skip the registration if CONFIG_MEMORY_HOTREMOVE
is not enabled and also call out when memory notifier registration fails.

Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Steve Capper <steve.capper@arm.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/1604896137-16644-2-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 1c0f3e02f731edd8b962b2d62a8954236b91c3d7..71dd9d753b8b69b6e5d08064b30adf18c9b68722 100644 (file)
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1510,7 +1510,16 @@ static struct notifier_block prevent_bootmem_remove_nb = {
 
 static int __init prevent_bootmem_remove_init(void)
 {
-       return register_memory_notifier(&prevent_bootmem_remove_nb);
+       int ret = 0;
+
+       if (!IS_ENABLED(CONFIG_MEMORY_HOTREMOVE))
+               return ret;
+
+       ret = register_memory_notifier(&prevent_bootmem_remove_nb);
+       if (ret)
+               pr_err("%s: Notifier registration failed %d\n", __func__, ret);
+
+       return ret;
 }
-device_initcall(prevent_bootmem_remove_init);
+early_initcall(prevent_bootmem_remove_init);
 #endif